BOISE — The Idaho Water Resource Board has agreed not to divert 200 cubic feet per second of streamflow under its recharge water rights from Dec. 1 through Feb. 15, allowing that amount of water to remain the Snake River for other uses, including hydropower production, below Milner Dam in the Magic Valley.

The Board passed a mid-November resolution agreeing to leave the water in the system.

The Board’s water rights for recharging Snake River surface flows into the Eastern Snake Plain Aquifer allow for the diversion of up to 7,769 acre-feet of water at or upstream of Milner Dam. Consistent with direction from the Idaho Legislature, the Board seeks to recharge an annual average of 250,000 acre-feet of water into the ESPA each year to restore the aquifer to sustainable levels.

Since 2015, when the ESPA recharge program began in earnest, about 2.2 million acre-feet of water has been added to aquifer storage from the Board’s recharge program and other management actions. In recent discussions regarding use and management of the Snake River flows above Milner during the winter time, Idaho Power Company officials noted that allowing some water to flow pastMilner Dam in the winter would be valuable for hydropower production.

Idaho Power has reduced its reliance on coal for electrical generation, and it needs to make up for that lost production with more renewable power production, officials said.

“The Board intends to work cooperatively with all stakeholders to explore opportunities to benefit all uses on the system,” Water Board Chairman Roger Chasesaid. “We learn as we go.”

The Board’s agreement not to divert a portion of its recharge water rights will be in effect for one year. If the Board does not reach 250,000 acre-feet of recharge during the winter of 2020-2021, the resolution calls on Idaho Power to provide replacement water for the shortfall from its American Falls Reservoir storage to ensure the Board meets its recharge goal.

“We should approve this resolution,” said Board member Vince Alberdi of Kimberly. “This speaks to the success of our recharge program.”

In other business, the Board voted to take a proactive role as the lead partner with the Bureau of Reclamation to help develop and finance the non-federal cost of raising Anderson Ranch Dam to ensure that the project stays on course. The estimated cost of raising the dam by 6 feet is an estimated $91 million, according to the Draft Environmental Impact Study.

The dam-raise project would add 29,000 acre-feet of water storage in the reservoir. The Bureau’s portion, based on identified federal benefits, would require authorization and funding under the WIIN Act (Water Infrastructure Improvements for the Nation Act). By taking a lead role in financing the non-federal portion of the project, the Board will likely issue revenue bonds and then sub-contract with water users to pay for the new reservoir space. The revenue bonds would be retired with payments from the water users over time, officials said.

The WIIN Act requires the non-federal cost of construction to be paid up-front. A final EIS on the project is expected to be completed in February 2021, and a Record of Decision in May. In other action, the Board:

•Approved up to $475,000 in Board funds to continue phase two of a four-year hydrologic characterization of the Raft River Basin. The project involves data-gathering and analysis, installation of stream gages and 40 monitoring wells, water quality sampling, and development of a conceptual hydrologic framework.

Ground water levels in the Raft River Basin have been declining about 1.75 feet per year in recent years. The project seeks to determine the issues causing the decline and a suite of recommendations to reverse it. The Idaho National Laboratory also is contributing $832,000 to the project through the Idaho Department of Environmental Quality. The Idaho Geologic Survey is also a partner in the project.

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